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Factor out common infix op logic

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Tangent Wantwight 2024-05-18 21:33:17 -04:00
parent 1078dc3653
commit 5a34b0f6f7
1 changed files with 14 additions and 32 deletions
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46
src/lib/expr.ts
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@ -58,44 +58,26 @@ function map(
} }
} }
function makeInfixOp(token:RegExp, leftBindingPower: number,rightBindingPower: number, op: (left: number, right: number) => Value | ErrorResult):TokenHandler {
return {
leftBindingPower,
token,
parse: ({ value: left }, matched, parser) =>
map(parser.parseSubExpression(rightBindingPower), (right) => op(left, right)),
}
}
const Operators: TokenHandler[] = [ const Operators: TokenHandler[] = [
{ {
leftBindingPower: -1, leftBindingPower: -1,
token: NUMBER_TOKEN, token: NUMBER_TOKEN,
parse: (left, matched) => ({ value: Number(matched) }), parse: (left, matched) => ({ value: Number(matched) }),
}, },
{ makeInfixOp(PLUS_TOKEN, 10, 11, (left, right) => ({ value: left + right })),
leftBindingPower: 10, makeInfixOp(MINUS_TOKEN, 10, 11, (left, right) => ({ value: left - right })),
token: PLUS_TOKEN, makeInfixOp(TIMES_TOKEN, 10, 11, (left, right) => ({ value: left * right })),
parse: ({ value: left }, matched, parser) => makeInfixOp(FLOOR_TOKEN, 10, 11, (left, right) => ({ value: Math.floor(left / right) })),
map(parser.parseSubExpression(11), (right) => ({ value: left + right })), makeInfixOp(DIV_TOKEN, 10, 11, (left, right) => ({ value: left / right })),
},
{
leftBindingPower: 10,
token: MINUS_TOKEN,
parse: ({ value: left }, matched, parser) =>
map(parser.parseSubExpression(11), (right) => ({ value: left - right })),
},
{
leftBindingPower: 20,
token: TIMES_TOKEN,
parse: ({ value: left }, matched, parser) =>
map(parser.parseSubExpression(21), (right) => ({ value: left * right })),
},
{
leftBindingPower: 20,
token: FLOOR_TOKEN,
parse: ({ value: left }, matched, parser) =>
map(parser.parseSubExpression(21), (right) => ({
value: Math.floor(left / right),
})),
},
{
leftBindingPower: 20,
token: DIV_TOKEN,
parse: ({ value: left }, matched, parser) =>
map(parser.parseSubExpression(21), (right) => ({ value: left / right })),
},
]; ];
const ZERO = { value: 0 }; const ZERO = { value: 0 };